Download Servo Valves Power Amplifier for Servo Valves

Vickers®
Servo Valves
Power Amplifier for Servo Valves
EHA-PAM-291-A-20
Front Panel; Actual Size
Wiring terminal clamp screws
General Description
The EHA-PAM-291-A-20 power amplifier
is designed for controlling Vickers SM4
servo-valves, or other servo-valves up to
200 mA max. current.
+24V power supply input, green LED
+24V
Potentiometers
Gain
Gain, offset and dither (frequency and
amplitude) are adjustable by
potentiometers mounted in the front
panel. An externally switched, 24V “drive
enable” signal is used to switch the
power drive on and off.
The amplifier is packaged as a
“snap-on” control module for mounting
into control cabinets using mounting rails
to DIN EN 50022 or DIN EN 50035.
Dither amplitude
Dither frequency
Offset
EHA-PAM291-A-20
Wiring terminal clamp screws
Features and Benefits
F LED shows when 24V power supply
is present
F Two test terminals allow dither
amplitude and gain setting (output
current) to be measured, simplifying
start-up and fault finding
F Output stage is short circuit protected
F “Drive enable/disable” controlled by
external signal
F Uni-polar voltage input; bi-polar
current output
This product has been designed and tested to meet specific standards outlined in the European Electromagnetic Compatibility
Directive (EMC) 89/336/EEC, amended by 91/263/EEC, 92/31/EEC and 93/68/EEC, article 5. For instructions on installation
requirements to achieve effective protection levels, see this leaflet and the Installation Wiring Practices for Vickers Electronic
Products leaflet 2468. Wiring practices relevant to this Directive are indicated by
Electromagnetic Compatibility (EMC).
January 1996
GB-2093A
Operating Data
Power supply
24V DC nominal (18 to 36V DC),
7W max. Ripple pk-to-pk v 4Vpp
Differential input signal
0 to " 10V (Ri = 47 kOhm)
(overload capacity up to max. " 25V)
Maximum output current
" 200 mA (" 300 mA at min. supply
voltage)
Gain:
Adjustment range
Factory setting
1 to 40 mA/V
4 mA/V
Offset:
Adjustment range
Factory setting
+ 40 to – 40 mA output current
0 mA
Drive enable
Drive disable
12 to 36V (Ri = 4,7 kOhm)
< 8V, or open circuit
0 to 20%
4%
150 to 500 Hz
400 Hz
Linearity
< 0,5%
Temperature coefficient
< 0,05% per _C (0.03% per _F)
–3 dB frequency response
> 1,5 kHz
Test terminals
(E and F measured against D):
E: output current
F: dither
1V = 500 mA
1V = 2,5% amplitude
Wiring recommendations, all
connections
0,5 to 2,5 mm2 (22 to 12 AWG)
Housing material
Polyamid 6.6
Protection
IEC 529 class IP20
Dither Amplitude
The dither amplitude is measured as a
perce t ge of the maximum
percentage
m im m value.
l e
Increase by turning the potentiometer
clockwise; decrease by turning
co nter-clockwise.
counter-clockwise.
Dither Frequency
Incre se by turning
Increase
t rning the potentiometer
clockwise; decrease by turning
counter-clockwise.
Offset
Turn the potentiometer clockwise to
g
obtain a negative
offset of output
current;
t counter-clockwise
t
l k i ffor a positive
iti
offset
offset.
Op
Operating
i g Range
g
If the required output current is above
200 mA and the load resistance is
below 50 Ohm, the power supply
voltage must be reduced in accordance
with
ith characteristics
h
t i ti shown.
h
+36V
Vibration:
Vickers environmental specification
Class I level 2 (IEC 68-2-6)
Electromagnetic compatibility (EMC):
Emission
Immunity
IEC 529 class IP20
EN 50081-2
EN 50082-2
Ambient temperature range:
Operational
Storage
0_ to +50_C (+32_ to +122_F)
–25_ to +85_C (–13_ to +185_F)
Mass
0,11 kg (0.24 lb)
Warning: Electromagnetic Compatibility (EMC)
It is necessary to ensure that the unit is wired up in accordance with the connection
arrangements shown in this leaflet. For effective protection, the user’s electrical
cabinet, the valve subplate or manifold and the cable screens should be connected
to efficient ground points. The metal 7-pin connector part no. 934939 should be used for the
integral amplifier.
In all cases, both valve and cable should be kept as far away as possible from any source of
electromagnetic radiation such as cables carrying heavy current, relays and certain kinds of
portable radio transmitters, etc. Difficult environments could mean that extra screening may be
necessary to avoid the interference.
2
Gain
Output current/input voltage
g ratio is
increased by turning the potentiometer
clockwise; decreased by turning
co nter-clockwise
counter-clockwise.
Power supply voltage
Dither amplitude:
Adjustment range
Factory setting
Dither frequency:
Adjustment range
Factory setting
Adjustments
j
200 mA
Output current
350 mA
Electrical Block Diagram
Drive enable, +24V
J
A
Power supply, +24V
Power 0V
Output current
M
L
24V
C
+ G
Voltage input
E
H
–
Dither
Offset
Current measuring point
D
F
Dither measuring point
Customer’s protective ground connection.
22,5
(0.9)
3rd angle
projection
K L M
G H J
Installation Dimensions in mm (inches)
“A” max. over DIN rail, see table
Type
TS1
TS3
TS4/5
A
107 (4.22) 102 (4.01) 109,5 (4.32)
A B C
D E F
75
(3.0)
3